Dawn, a NASA spacecraft, has arrived at Ceres, a dwarf planet and the largest member of the of our solar system's asteroid belt. In an orbit that will spiral ever closer until it reaches its optimal altitude, Dawn will continue taking pictures of Ceres, and eventually map its entire surface. Even the initial images are surprising scientists back here on earth with new unexpected data.
The most interesting feature on Ceres heretofore has been an area which is much brighter than the rest of its surface. Scientists have seen this area in images from the Hubble space telescope, but, starting in February of this year, images sent back by Dawn have been much more detailed, about three times the resolution of images from Hubble. The Dawn images are, for the first time, showing that the bright area changes in brightness as Ceres revolves, once every nine hours, and the area moves into and out of the light and warmth of the sun. As Dawn has gets closer, the images it is sending back are getting more and more detailed. Very recently they have shown a plume being ejected from Ceres' surface, causing scientists to start asking all sorts of questions. Is the plume water? Does this mean that under Ceres' crust there might be an ocean? Scientists already know from its effect on other bodies near it, that Ceres must have some large amounts of water or ice on it, which effects that dwarf planet's over-all density. Scientists have already been reasoning that if there is cryovolcanism, that is, volcanoes where ice is behaves the way lava and volcanic ash do here on earth, there must be enough heat and energy to move water in this way. And where there is water and energy there may be life, not on Ceres' surface, which is lacking an atmosphere, but possibly in an ocean below the surface.
But the plume may be caused by some other process. The Rosetta probe, for example, has sent back images plumes being ejected from comet P/67 Churyumov-Gerasimenko that are caused by sublimation, that is the passing of a substance from solid to gas without passing through a liquid state. To know definitively what the plume is and what causes it scientists will need more information, but they'll have it soon. Each of Dawn's orbits bring it closer to Ceres, and so the images will get more detailed and so contain more information.
By the beginning of April, Dawn will reach its optimal orbit where it will begin systematically mapping of the surface of Ceres. As that data filters back to Earth, scientists will get to know, and start to name every crater and plane, the same way they have already done with our moon. Cleary the members of the International Astronomical Union have been anticipating this process. They have already ruled that since Ceres is named after the roman goddess of the harvest, craters there will be named after other gods and goddesses of agriculture, and other features will be named after harvest celebrations and festivals from around the world.
Source: Phys.org
